Removable four implant-supported mandibular overdentures rigidly retained with telescopic crowns or milled bars: a 3-year prospective study

Purpose: The present study evaluated implant survival/success rate, peri‐implant parameters and prosthodontic maintenance efforts for four implant‐supported mandibular overdentures (IOD) rigidly retained on either milled bar or double crowns (telescopic) attachments. Material and methods: In a randomized prospective trial, 51 patients with edentulism received four mandibular interforaminal implants and complete maxillary dentures. For IOD, rigid denture stabilization was chosen randomly selecting 26 patients for milled bars (group I) and 25 patients for double (telescopic) crowns (group II). During a 3‐year follow‐up period, implant survival/success, peri‐implant parameters (marginal bone resorption, pocket depth, plaque‐, bleeding‐, gingival index [BI and GI], calculus) and prosthodontic maintenance efforts were evaluated and compared between both retention modalities used. Results: Forty‐five patients (23 group I, 22 group II) were available for a 3‐year follow‐up (dropout rate: 11.8%) presenting a high implant survival/success rate (100%). Peri‐implant marginal bone resorption, pocket depth as well as BI and GI did not differ for both rigid retention modalities. However, annually higher values for plaque‐ (NS) and calculus index (P<0.035) were noticed for the bar (group I) than for the telescopic crown (group II) attachments. Prevalence of prosthodontic maintenance did not differ between both retention modalities (group I: 0.41/maintenance efforts/year/patients vs. group II; 0.45 maintenance/efforts/year/patients). However, prosthodontic adaption for handling mechanism showed benefits for the bar retention. Conclusion: Rigid anchoring of IOD retained either by bar or telescopic attachments showed high implant success rates and minor prosthodontic maintenance efforts regardless of retention modalities used. Stable denture retention presented healthy peri‐implant structure for implants in bar and telescopic anchoring systems. Drawbacks such as higher plaque/calculus for bar retention and less favorable handling properties (output) for telescopic crown attachment leave the decision on the selection at the discretion of the clinician. To cite this article:
Krennmair G, Sütö D, Seemann R, Piehslinger E. Removable four implant‐supported mandibular overdentures rigidly retained with telescopic crowns or milled bars: a 3‐year prospective study.
Clin. Oral Impl. Res. 23 , 2012 481–488.
doi: 10.1111/j.1600‐0501.2011.02169.x     

Long-term outcomes of three types of implant-supported mandibular overdentures in smokers

Purpose: The aim of the study was to compare the differences in the long‐term clinical and radiologic effects for three different treatment strategies with implant‐supported overdentures in the edentulous mandible, with a special emphasis on smoking. Materials and methods: In a randomized‐ controlled clinical trial, 110 edentulous patients participated. Thirty‐six patients were treated with an overdenture supported by two implants with ball attachments (2IBA), 37 patients with an overdenture supported by two implants with a bar (2ISB) and 37 patients with an overdenture supported by four implants with a triple bar (4ITB). After a mean evaluation period of 8.3 years, the clinical and radiographic parameters were evaluated. Results: Ninety‐four out of the original 110 patients (=85%) were evaluated. In the 2IBA group, the plaque index was significantly lower (vs. 2ISB, P=0.013; vs. 4ITB, P=0.001) than in the other groups, but there was no correlation with the other peri‐implant parameters. In the 4ITB group, the marginal bone loss was significantly higher than that in the two implant groups. The maximal probing depth was correlated with peri‐implant bone loss (P=0.011). Smoking almost doubled marginal bone loss irrespective of the treatment strategy chosen. Conclusions: Patients with two implants show less marginal bone loss than those with four implants. Smoking is a risk factor for the survival of dental implants in the long run. To cite this article :
Stoker G, van Waas R, Wismeijer D. Long‐term outcomes of three types of implant‐supported mandibular overdentures in smokers.
Clin. Oral Impl. Res. 23 , 2012; 925–929
doi: 10.1111/j.1600‐0501.2011.02237.x     

Prospective Evaluation of 2,549 Morse Taper Connection Implants: 1‐ to 6‐Year Data

Background: The aim of this study is to evaluate the implant survival, the implant–crown success, and the prosthetic complications of 2,549 Morse taper interference–fit connection implants. Methods: A total of 2,549 Morse taper connection implants were inserted in 893 patients from January 2003 until December 2008. At each annual recall, clinical, radiographic, and prosthetic parameters were assessed. The implant–crown success criteria included the absence of pain, suppuration, and clinical mobility; an average distance between the implant shoulder and the first visible bone contact <2 mm from initial surgery; and the absence of prosthetic complications at the implant–abutment interface. Prosthetic restorations were fixed partial prostheses (462 units); fixed full‐arch prostheses (60 units); single crowns (531 units); and overdentures (93 units). Results: The cumulative implant survival rate was 98.23% (97.25% maxilla, 99.05% mandible). The implant–crown success was 92.49%. A few prosthetic complications at implant–abutment interface were reported (0.37%). After 6 years, distance between the implant shoulder and the first visible bone contact was 1.10 mm (± 0.30 mm). Conclusion: The use of Morse taper connection implants represents a successful procedure for the rehabilitation of partially and completely edentulous arches.     

Immediate loading of mandibular overdentures supported by unsplinted direct laser metal-forming implants: results from a 1-year prospective study

Background: At present, only some studies have dealt with immediate loading of unsplinted implants supporting mandibular overdentures. The aim of this prospective study is to evaluate treatment outcomes of mandibular overdentures supported by four one‐piece, unsplinted, immediately loaded, direct laser metal‐forming (DLMF) implants by assessing implant survival rate, implant success, marginal bone loss, and prosthetic complications. Methods: A total of 96 one‐piece DLMF implants were inserted in the edentulous mandible of 24 patients. Four implants were placed in each edentulous mandible. Immediately after implant placement, a mandibular overdenture was connected to the implants. At 1‐year follow‐up, clinical, radiographic, and prosthetic parameters were assessed. Success criteria included absence of pain, suppuration, and implant mobility; absence of continuous peri‐implant radiolucency; and distance between the implant shoulder and the first visible bone contact <1.5 mm. Results: After a 1‐year loading time, the overall implant survival rate was 98.9%, with only one implant lost. Among the surviving 95 implants, two did not fulfill the success criteria; therefore, the implant success rate was 97.8%. The mean distance between the implant shoulder and the first visible bone contact was 0.28 ± 0.30 mm (95% confidence interval, 0.24 to 0.32). Some prosthetic complications were reported. Conclusion: Based on the present results and within the limits of this study, the immediate loading of four unsplinted DLMF implants by means of ball attachment–supported mandibular overdentures seems to represent a safe and successful procedure.     

Prospective clinical evaluation of 1920 Morse taper connection implants: results after 4 years of functional loading

Purpose: This study evaluated the survival rate and the clinical, radiographic and prosthetic success of 1920 Morse taper connection implants.
Material and methods: One thousand nine hundred and twenty Morse taper connection implants were inserted in 689 consecutive patients, from January 2003 until December 2006. Implants were clinically and radiographically evaluated at 12, 24, 36 and 48 months after insertion (mean follow-up per implant: 25.42 months). Modified plaque index (mPI), modified sulcus bleeding index, probing depth (PD) and the distance between implant shoulder and first crestal bone–implant contact (DIB) were measured in mm. Success criteria included the absence of suppuration and clinically detectable implant mobility, PD<5 mm, DIB<1.5 mm after 12 months of functional loading and not exceeding 0.2 mm for each following year, the absence of recurrent prosthetic complications at the implant–abutment interface. Prosthetic restorations were fixed partial prostheses (364 units), single crowns (SCs: 307 units), fixed full-arch prostheses (53 units) and overdentures (67 units).
Results: The overall cumulative implant survival rate was 97.56% (96.12% in the maxilla and 98.91% in the mandible). The cumulative implant success rate was 96.61% (95.25% in the maxilla and 98.64% in the mandible). Only a few prosthetic complications were reported (0.65% of loosening at implant–abutment interface in SCs).
Conclusion: The use of Morse taper connection implants represents a successful procedure for the rehabilitation of partially and completely edentulous arches. The absence of an implant–abutment interface (microgap) is associated with minimal crestal bone loss. The high mechanical stability significantly reduces prosthetic complications.     

Mandibular single‐implant overdentures: preliminary results of a randomised‐control trial on early loading with different implant diameters and attachment systems

Objectives: To determine surgical and prosthodontic outcomes of mandibular single‐implant overdentures, opposing complete maxillary dentures, using a wide diameter implant and large ball attachment system compared with different regular diameter implants with standard attachment systems. Materials and methods: Thirty‐six edentulous participants (mean age 68 years, SD 9.2) were randomly assigned into three treatment groups (n=12). A single implant was placed in the mandibular midline of participants to support an overdenture using a 6‐week loading protocol. The control group received Southern regular implants and standard ball attachments. One group received Southern 8‐mm‐wide implants and large ball attachments. Another group received Neoss regular implants and Locator attachments. Parametric and non‐parametric tests of a statistical software package (SPSS) were used to determine between groups differences in marginal bone loss, implant stability, implant, and prosthodontic success (P<0.05). Results: Implant success after 1 year was 75% for Southern regular implant (control) group; and 100% for the Southern wide and Neoss regular implant groups (P=0.038). Mean marginal bone loss at 1 year was 0.19 mm (SD 0.39) without significant differences observed. Implant stability quotient (ISQ) at baseline was significantly lower for the Southern regular (control) group than the other two groups (P=0.001; P=0.009). At 1 year, no significant difference in implant stability was observed (mean ISQ 74.6, SD 6.1). The change in implant stability from baseline to 1 year was significant for the control group (P=0.025). Prosthodontic success was comparable between the groups but the maintenance (41 events overall, mean 1.2) was greater for the Locator and the standard ball attachments. Conclusions: Mandibular single‐implant overdentures are a successful treatment option for older edentulous adults with early loading protocol using implants of different diameters and with different attachment systems. To cite this article:
Alsabeeha NHM, Payne AGT, De Silva RK, Thomson WM. Mandibular single‐implant overdentures: preliminary results of a randomised‐control trial on early loading with different implant diameters and attachment systems.
Clin. Oral Impl. Res. 22 , 2011; 330–337.
doi: 10.1111/j.1600‐0501.2010.02004.x     

An analysis of the implant‐supported overdenture in the edentulous mandible

This investigation examined the cumu‐lative survival rate of the implant‐supported overdenture using two types of attachments in patients treated at Show Chwan Memorial Hospital Implant Center from 1992 to 2006. Fifty‐one patients (30 men and 21 women) were treated with mandibular implant‐supported overdentures. Attachment systems used were the Hader bar with bilateral, cast ERA attachments (Group A, 31 patients with 15 men and 16 women, 134 implants) and the Hader bar with bilateral, distal extension cantilevers (Group B, 20 patients with 15 men and 5 women, 85 implants). Two hundred and four implants remained at the end of the follow‐up period. Among failed implants, 10 implants were in Group A (failure rate: 10/134 = 7·5%), whereas five implants were in Group B (failure rate: 5/85 = 5·9%). Sixty‐six point seven per cent (10/15) of failed implants were placed in the distal anterior mandible, and 33·3% (5/15) were placed in the middle anterior mandible. Survival was also examined with respect to condition of the opposing arch. Patients wearing a maxillary removable partial denture had the highest implant failure rate (5/51 = 9·8%), whereas the failure rate of the maxillary complete denture group was only 5·7%. The most frequent need for maintenance was wear over patrix component of ERA or Hader clip (n = 56). Eight patients experienced connector fracture between ERA and Hader bar, and one experienced distal extension cantilever fracture. The implant‐supported overdenture can be an effective and reliable alternative to the conventional complete mandibular denture. Fewer prosthetic complications were seen in overdentures retained with distal extension cantilever attachments.     

Resilient liner vs. clip attachment effect on peri‐implant tissues of bar‐implant‐retained mandibular overdenture: a 1‐year clinical and radiographical study

Purpose: The aim of this study was to compare between the effects of resilient liner and clip attachments of bar‐implant‐retained mandibular overdenture on peri‐implant tissues. Materials and methods: In a randomized‐controlled clinical trial, 30 edentulous male patients (mean age 62.5 years) were equally assigned to two groups. In each patient, two implants were inserted in the canine area of the mandible using a two‐stage surgical protocol. After 3 months, the implants were connected with resilient bars. Mandibular overdentures were retained to the bars with either clips (group I) or silicone‐resilient liners (group II). Peri‐implant tissues were evaluated clinically (with regard to plaque scores, gingival scores and probing depths) and radiographically (with regard to peri‐implant vertical and horizontal alveolar bone changes). Evaluations were performed at the time of overdenture insertion (T0), 6 months (T6) and 12 months (T12) after overdenture insertion. Results: After 12 months of using bar‐implant‐retained mandibular overdenture, the resilient liner attachment had significantly decreased peri‐implant plaque score, gingival score, probing depth, vertical and horizontal bone loss when compared with the clip attachment. Conclusion: Within the limitations of this study, and in terms of peri‐implant tissue health of bar‐implant‐retained mandibular overdenture, we recommend resilient liner rather than clip attachment. To cite this article:
Elsyad MA, EL Shoukouki AH. Resilient liner vs. clip attachment effect on peri‐implant tissues of bar‐implant‐retained mandibular overdenture: a 1‐year clinical and radiographical study.
Clin. Oral Impl. Res. 21 , 2010; 473–480
doi: 10.1111/j.1600‐0501.2009.01879.x     

The influence of resilient liner and clip attachments for bar‐implant‐retained mandibular overdentures on opposing maxillary ridge. A 5‐year randomised clinical trial

This study aimed to compare the influence of resilient liner and clip attachments for bar‐implant‐retained mandibular overdentures on opposing maxillary ridge after 5 years of denture wearing. Thirty edentulous male patients (mean age 62·5 years) received two implants in the anterior mandible after being allocated into two equal groups using balanced randomisation. After 3 months, implants were connected with resilient bars. New maxillary complete dentures were then constructed, and mandibular overdentures were retained to the bars with either clips (group I, GI) or silicone resilient liners (group II, GII). The prosthetic and soft tissue complications of the maxillary dentures were recorded 6 months (T_6 m), 1 year (T1), 3 years (T3) and 5 years (T5) after overdenture insertion. Traced rotational tomograms were used for measurements of maxillary alveolar bone loss. The proportional value between bone areas and areas of reference not subject to resorption was expressed as a ratio (R). Change in R immediately before (T0) and after 5 years (T5) of overdenture insertion was calculated. Maxillary denture relining times and frequency of flabby anterior maxillary ridge occurred significantly more often in GI compared with GII. The change of R in anterior part of maxilla was significantly higher than change of R in posterior part in both groups. GI showed significant resorption of anterior residual ridge compared with GII. Relining times and frequencies of flabby ridge were significantly correlated with change in R. Within the limitations of this study, resilient liner attachments for bar‐implant‐retained mandibular overdentures are associated with decreased resorption and flabbiness of maxillary anterior residual ridge and fewer maxillary denture relining times when compared with clip attachments.     

Immediate Loading of Two Implants with a Mandibular Implant‐Retained Overdenture: A New Treatment Protocol

Purpose: The aim of this study was to present the clinical outcomes of the immediate loading of two bar‐splinted implants retaining a mandibular overdenture. Materials and Methods: In a clinical trial, 124 edentulous patients were treated according to a new treatment concept, which involves the immediate loading of two bar‐splinted SLActive implants with an implant‐retained mandibular overdenture. The new conventional mandibular denture is used as a template for implant positioning and as an impression tray, and for mounting the retention clip by the dental laboratory. At the same day the implants are placed, the conventional denture is converted into an implant‐retained overdenture. During the healing and evaluation period, resonance frequency analysis (RFA) was undertaken to assess the effect of loading on implant stability and survival. Results: The survival rate of the implants was 98.8% during the evaluation period (12–40 months). Only 3 of the 248 implants were lost. During the healing (osseointegration) phase, the implant‐stability quotient increased significantly (p = .0001). During the evaluation period, four patients (3%) needed a relining of their mandibular overdenture, whereas 13 patients (11%) needed relining of the maxillary denture. Conclusions: Two interconnected implants can be successfully loaded by a mandibular overdenture at the same day of implant placement with a high survival rate of the implants. Only a few patients needed additional relining of the overdenture. Repeated RFA measurements can be useful in gauging implant stability and survival.     

Marginal bone resorption around immediate and delayed loaded implants supporting a locator‐retained mandibular overdenture. A 1‐year randomised controlled trial

The aim of this 1‐year study was to evaluate and compare crestal bone loss and clinical outcomes of immediate and delayed loaded implants supporting mandibular overdentures with Locator attachments. In a randomised controlled clinical trial, 36 completely edentulous patients (mean age 59·6 years) who desired to improve the stability of their mandibular dentures were randomly assigned into two groups. Each patient received two implants in the canine area of the mandible after a minimal flap reflection. Implants were loaded by mandibular overdentures either 3 months (delayed loading group, G1) or the same day (immediate loading group, G2) after implant placement. Locator attachments were used to retain all overdentures to the implants. Peri‐implant vertical (VBL) and horizontal (HBLO) bone losses and clinical parameters [plaque scores (PI), gingival scores (GI), probing depths (PD) and implant stability (ISQ)] were assessed at time of overdenture insertion (T0), 6 months (T6) and 12 months (T12) after overdenture insertion. After 12 months of overdenture insertion, two implants (5·5%) failed in G2. Vertical bone loss was significantly higher in G2 compared with G1, while HBLO demonstrated insignificant differences between groups. All clinical parameters (PI, GI, PD and ISQ) did not differ significantly between groups. Vertical bone loss was significantly correlated with PD and HBLO. Immediately loaded two implants supporting a Locator‐retained mandibular overdenture are associated with more vertical bone resorption when compared to delayed loaded implants after 1 year. Clinical outcomes do not differ significantly between loading protocols.     

One-Year Prospective Evaluation of the Early Loading of Unsplinted Conical Brånemark Fixtures with Mandibular Overdentures Immediately following Surgery

Background: Prospective evaluation of the early loading of unsplinted Branemark implants with mandibular over‐dentures opposing conventional dentures is not evident in the implant‐related literature. Purpose: To clinically evaluate progressive and early loading of 20 unsplinted conical Brånemark implants in edentulous mandibles with overdentures. Materials and Methods: Ten edentulous patients all had two conical Brånemark implants placed in the anterior mandible with mandatory primary stability with bicortical anchorage. Ball abutment connection was performed simultaneously. Previously constructed conventional mandibular dentures were temporarily relined with tissue conditioner postoperatively and worn with moderation for the first 2 weeks to allow progressive loading. Early loading of the implants followed after 2 weeks, with inclusion of the respective matrices in the mandibular dentures, using a definitive reline procedure. Results: All patients successfully functioned with their mandibular implant overdentures from 2 to 52 weeks postoperatively. Mean marginal bone loss was within established criteria for success:0.22 mm (SD = 0.48 mm) mesially and 0.30 mm (SD = 0.39 mm) distally on the conical implants. Mobility tests using the Periotest instrument became more negative, although not at statistically significant levels. Difficulties in the management of the peri‐implant mucosa between surgery and loading at 2 weeks were observed in 40% of the patients. Conclusions: These preliminary 1‐year results show that successful early loading of unsplinted conical Brånemark implants with mandibular overdentures is possible.     

The effect of maximum bite force on marginal bone loss of mini‐implants supporting a mandibular overdenture: a randomized controlled trial

Objectives: To evaluate the effect of maximum bite force (mBF) on marginal bone loss (MBL) around mini‐implants in edentulous patients wearing mandibular overdentures with two retention systems: ball and bar. Material and methods: Forty‐five totally edentulous patients were selected from a public health center. All of them received two mini‐implants (1.8 × 15 mm; Sendax^®) in the anterior mandible using a minimally invasive technique. A single randomization was performed to allocate the patients in two groups. Group I (n=22) received two single ball‐type mini‐implants and Group II (n=23) received two mini‐implants splinted with a prefabricated bar. The mBF was recorded using a press‐sensitive sheet Dental Prescale^® (Fuji) and MBL using standardized radiographs of each mini‐implant at the baseline and 5, 7, 10, and 15 months after surgery; the values were compared between groups. Results: Two members of Group I failed to complete the study, decreasing the number of participants to 20. There was no relationship between the mBF and the MBL of the mini‐implants (Spearman's ρr_s=0.147; P=0.378). At the 15‐month follow‐up, the average mBF for Group I (ball) was 247.53 ± 132.91 N and that of Group II (bar) only 203.23 ± 76.85 N (Mann–Whitney test; P=0.586). The MBL values were also higher for Group I (1.40 ± 1.02 mm) than Group II (0.84 ± 0.66 mm) during the entire 15‐month follow‐up period (Mann–Whitney test; P=0.077). Conclusions: No relationship was found between mBF and MBL for patients wearing overdentures retained on mini‐implants using bar or ball attachment systems. To cite this article:
Jofré J, Hamada T, Nishimura M, Klattenhoff C. The effect of maximum bite force on marginal bone loss of mini‐implants supporting a mandibular overdenture: a randomized controlled trial.
Clin. Oral Impl. Res. 21 , 2010; 243–249.
doi: 10.1111/j.1600‐0501.2009.01834.x     

Oral Rehabilitation with Implant‐Retained Overdenture in a Patient with Down Syndrome

Down syndrome, known as trisomy 21, is the most common chromosomal disorder. The disorder affects mental and systemic development as well as oral structure, including dental anomalies, high susceptibility of periodontal disease, and poor quality of alveolar bone. This report presents a case of dental rehabilitation by means of dental implants of a patient with Down syndrome. Two titanium dental implants were placed in the maxilla, and three titanium dental implants were installed in the mandible. One implant was lost during the osseointegration period. The prosthetic rehabilitation was performed with implant‐retained maxillary and mandibular overdentures with the Locator attachment system. After a 2‐year follow‐up period, the patient was doing well, and all implants were clinically stable with no signs of bone loss or inflammation. The present study emphasizes that implant‐retained overdentures with Locator attachment system could be a therapeutic option even for patients with Down syndrome. This therapy prevents crestal bone loss around the implants, improves functional and esthetic outcomes, and provides optimum oral hygiene for patients with mild mental impairment. Careful patient selection and education of patients and caregivers are essential considerations for a successful and safe treatment with dental implants in Down syndrome patients.     

Marginal bone loss adjacent to conventional and immediate loaded two implants supporting a ball-retained mandibular overdenture: a 3-year randomized clinical trial

Objectives: The aim of this study was to evaluate and compare marginal bone loss and clinical outcomes of conventionally and immediately loaded two implants supporting a ball‐retained mandibular overdenture. Materials and methods: Thirty six completely edentulous patients (22 males and 14 females) were randomly assigned into two groups. Each patient received two implants in the canine area of the mandible after a minimal flap reflection. Implants were loaded by mandibular overdentures either 3 months (conventional loading group) or the same day (immediate loading group) after implant placement. Ball attachments were used to retain all overdentures to the implants. Vertical and horizontal alveolar bone losses were evaluated in both groups 1 and 3 years after implant placement using multislice computed tomography, which allow evaluation of peri‐implant buccal and lingual alveolar bone. Plaque scores, gingival scores, probing depths and periotest values (PTVs) were evaluated at 4 months (baseline), 1 and 3 years after implant placement. Clinical and radiographic evaluations were performed at distal, labial, mesial and lingual peri‐implant sites. Results: After 3 years of follow‐up period, the immediate loading group recorded significant vertical bone loss at distal and labial sites than the conventional loading group and no significant differences in horizontal bone loss between groups were observed. Probing depth at distal and labial sites in the immediate loading group were higher than the conventional loading group, while plaque scores, gingival scores and PTVs showed no significant differences between the two groups. A low level of positive correlation between plaque scores, gingival scores, probing depths and vertical bone loss was noted. Conclusion: Immediately loaded two implants supporting a ball‐retained mandibular overdenture are associated with more marginal bone resorption and increased probing depths when compared with conventionally loaded implants after 3 years. The bone resorption and probing depths at distal and labial sites are significantly higher than those at mesial and lingual sites. Clinical outcomes do not differ significantly between loading protocols. To cite this article :
Elsyad MA, Al‐Mahdy YF, Fouad MM. Marginal bone loss adjacent to conventional and immediate loaded two implants supporting a ball‐retained mandibular overdenture: a 3‐year randomized clinical trial.
Clin. Oral Impl. Res. 23 , 23, 2012 496‐503.
doi: 10.1111/j.1600‐0501.2011.02173.x     

Early functional loading of unsplinted roughened surface implants with mandibular overdentures 2 weeks after surgery

Background: Before early functional loading of unsplinted implants with mandibular overdentures can become widespread, more clinical studies are needed to investigate the success of the approach. Purpose: To evaluate the success rates of two types of roughened titanium surface implants with early 2‐week functional loading of paired mandibular interforaminal implants with overdentures. Materials and Methods: Random allocation divided 24 strictly selected edentulous participants into two groups, with each group to receive a different implant system (ITI Dental Implant System, Straumann AG, Waldenburg, Switzerland; or Southern Implant System, Southern Implants, Irene, South Africa). Two implants were placed in the anterior mandible of all participants using one‐stage standardized surgical procedures. Previously constructed conventional mandibular dentures (opposing maxillary complete dentures) were temporarily relined and worn by the participants for the first 2 weeks; participants used a soft diet. Two weeks after implant surgery and following some mucosal healing, the mandibular dentures had the tissue conditioner removed and the appropriate matrices included for an unsplinted prosthodontic design. Results: No implant from either group was lost. Resonance frequency analysis (RFA) indicated higher primary stability at surgery for the Southern group than for the ITI group, with a statistically significant difference between the groups throughout the study period. The drop in RF values between surgery and 6 weeks was significant and was greater for the Southern group. RFA also indicated stabilized osseointegration between 6 to 12 and 12 to 52 weeks, with no participant showing any decrease in those values over time. Participants with type 3 bone showed a significant improvement in RF values between 12 and 52 weeks, eventually matching those of participants with type 2 bone. There were no significant differences in marginal bone loss, periimplant parameters, or prosthodontic maintenance between the groups over the study period. Conclusions: Using only strict patient selection criteria, 1‐year follow‐up data indicate that early functional loading of ITI and Southern implants with mandibular two‐implant overdentures is possible as early as 2 weeks after implant surgery.     

One-stage operative procedure using two different implant systems: a prospective study on implant overdentures in the edentulous mandible

Background: Evidence‐based reports are needed to support the application of a one‐stage surgical protocol for unsplinted implants supporting mandibular overdentures. Purpose: To examine the feasibility and success of using two different dental implant systems (originally designed for two‐stage operative technique) using a one‐stage operative procedure in patients being rehabilitated with implant mandibular overdentures. Materials and Methods: The study sample involved 24 edentulous subjects (aged 55–80 yr) randomly allocated to two different implant systems, one with a machined titanium implant surface (Steri‐Oss, Nobel Biocare, Göteborg, Sweden) and the other with a roughened titanium surface (Southern Implants, Ltd., Irene, South Africa). Two unsplinted implants to support implant overdentures were placed in the anterior mandible of all patients, using a standardized one‐stage surgical and prosthodontic procedure. Primary stability and bicortical anchorage of the implants was mandatory before healing abutments were connected at the time of implant placement. Implant overdentures and their respective matrices were inserted following a standard 12‐week healing period. Data relating to mobility tests, radiographs, and peri‐implant parameters were documented at 12, 16, and 52 weeks after surgery. Results: A success rate of 95.8% for the Steri‐Oss and 100% for the Southern Implants was found, without any statistically significant differences in the marginal bone loss. Significant changes in Periotest values were observed for both types between 12 and 52 weeks (p <.001). Minor changes were observed in the peri‐implant parameters evaluated. Conclusions: These preliminary findings show a successful application of this one‐stage approach for unsplinted implants supporting mandibular overdentures with Steri‐Oss and Southern Implant Systems.     

A long-term study of implants supporting overdentures as a model for implant success

BACKGROUND: Implant-supported overdentures have been a common treatment for edentulous patients for the past 20 years, achieving good clinical results. The purpose of this study was to examine survival and success rates of implants supporting overdentures in the maxilla and mandible and to examine the influence of factors related to patients, implant procedure, implant data, and follow-up period on implant success. METHODS: During a 10-year period (1990 to 2000), 285 implants were placed in 62 patients to support 69 overdentures (seven patients had overdentures in both jaws). Patients ranged in age from 45 to 85 years (mean 64.5 years). The files of 61 patients, including 277 implants supporting 68 overdentures (14 maxillary and 54 mandibular), had measurable radiographic post-exposure follow-up (range 6.63 to 110.93 months, mean 37.93 months) for cervical bone loss (CBL) measurements. Bone loss was measured by radiographic examination in which the mean number of exposed threads in mesial and distal sides of the implant was considered. Implants were rehabilitated by overdentures with bar (N = 52) or ball (N = 16) attachments. RESULTS: Implant survival rate was 96.1% (11/285 did not survive) and total 10-year cumulative survival rate was 95.4% (maxilla, 83.5%, mandible, 99.5%). The success rate was 70.4% (maxilla, 41.9%; mandible, 80.8%) when using Albrektsson et al. success criteria. A logistic regression analysis showed that the maxilla (P <0.0001) and a short follow-up period (up to 5 years) (P = 0.017) were the most influencing factors enhancing CBL. CONCLUSIONS: 1) Survival of implants supporting overdentures was very high; 2) implants supporting overdentures in the maxilla had greater CBL than in the mandible; and 3) new criteria of implant success should be considered.     

Mandibular implant‐supported overdentures and oral function

Objectives: Oral rehabilitation by means of implant‐retained mandibular overdentures is known to improve oral function. The aim of this study was to evaluate the long‐term effects of mandibular implant treatment on oral function. We quantified maximum bite force and masticatory performance 10 years after implant treatment. It was hypothesized that these outcome measures would not change in this period. Materials and methods: Eighteen edentulous patients were scheduled for re‐evaluation of their oral function 10 years after they had participated in a randomized cross‐over clinical trial. In that trial, they had received two mandibular implants and a new denture with successively magnet‐, ball‐socket, and bar‐clip attachments. Results: At the 10‐year follow‐up, 14 of the initial 18 patients participated in the evaluation. As a result of the implant treatment, the average maximum bite force more than doubled, from 162 to 341 N, whereas the average number of chewing cycles to halve the initial partcle size decreased from 55 to 27 cycles. No significant changes in maximum bite force and masticatory performance were observed after 10 years. However, the average maximum bite force obtained with implant‐retained overdentures is still significantly lower than that of dentate subjects (569 N). Conclusion: Maximum bite force and masticatory performance significantly increased after implant treatment and remained unaltered during the following 10‐year period. Thus, implant treatment greatly improves oral function for a long period of time. To cite this article:
van der Bilt A, Burgers M, van Kampen FMC, Cune MS. Mandibular implant‐supported overdentures and oral function.
Clin. Oral Impl. Res. 21 , 2010; 1209–1213.
doi: 10.1111/j.1600‐0501.2010.01915.x     

Early loading of unsplinted implants supporting mandibular overdentures using a one-stage operative procedure with two different implant systems: a 2-year report

Background: Step‐wise reduction in loading protocols is necessary to evaluate early loading of implants with mandibular overdentures. Purpose: To compare the success rates of two different dental implant systems following conventional or early loading protocols in patients being rehabilitated with mandibular overdentures. Materials and Methods: Forty‐eight edentulous participants were randomly allocated to two different implant systems: one with a machined titanium implant surface (Sterioss, Nobel Biocare, Yorba Linda, California, USA) and the other with a roughened titanium surface (Southern Implants, Irene, South Africa). For each system, the participants were further divided into control groups, in whom mandibular implant overdentures and their respective matrices were inserted following a standard 12‐week healing period, and test groups, in whom a 6‐week healing period was followed prior to identical loading. Two unsplinted implants to support implant overdentures were placed in the anterior mandible of all participants, using a standardized one‐stage surgical procedure. Mobility tests and marginal bone levels, as well as periimplant parameters, were evaluated at each baseline and 52 and 104 weeks after surgery. Results: There was no statistically significant difference in the success rates of the two systems in either control or test groups. At the 2‐year evaluation, a success rate was found of 87.5% and 70.8.% for the control and test Sterioss groups, respectively, and 83.3% and 100% for the control and test Southern Implants groups were observed. For the Sterioss groups, eight implants were lost at an early stage: seven in the test group and one in the control group. For the Southern Implants control and test groups, no failures were seen at any time interval. There were no significant differences in marginal bone loss, Periotest values, and peri‐implant parameters between implant systems or between any of the control or test groups. Conclusions: Early loading, with step‐wise reductions in loading protocols, of unsplinted machined Sterioss and roughened Southern Implants fixtures with mandibular overdentures is possible for up to 2 years.